<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="root"></div>
    <script src="https://unpkg.com/react@18/umd/react.development.js" crossorigin></script>
    <script src="https://unpkg.com/react-dom@18/umd/react-dom.development.js" crossorigin></script>
    <script src="https://unpkg.com/babel-standalone@6/babel.min.js"></script>
    <script type="text/babel">
        class MyComponent extends React.Component{
            constructor(props){
                super(props);
                this.state = {
                    count:0
                };
            }
            handleClick = () => {
                this.setState({
                    count:this.state.count + 1
                });
            }
            render(){
                return <div>
                    计数器：<span>{this.state.count}</span>
                    <input type="button" value="+1" onClick={this.handleClick} />
                    <Sub count={this.state.count}></Sub>
                </div>
            }
        }
        class Sub extends React.Component{
            constructor(props){
                super(props);
            }
            render(){
                return <p>
                    {this.props.count}
                </p>
            }
        }
        ReactDOM.createRoot(document.getElementById("root")).render(<MyComponent />);

    </script>
</body>
</html>